Thread-heating means for sewing machines



May 4,1926. 1,583,757

P. W. VALENTINE THREAD HEATING MEANS FOR SEWING MACHINES Filed Sept. 27. 1924 2 Sheets-Sheet 1 May 4 1926.

P. W..VALENTINE THREAD HEATING MEANS FOR SEWING MACHINES Filed Sept. 27) 1924' 2 Sheets-Sheet 2 Patented May 4, 1926.

UNITED. STAT ES PATENT wics.

PERCY W. VALENTINE 0F CAMBRIDGE, MASSACHUSETTS, ASSIGNOR iGF ONE-.HALF

pro LLoYn 1.. LIVINGSTON, OFABIN-GTGN," MASSACHUSETTS.

THREAD-HEATING means son snwms MAeHnvns;

" Application fil ed September, 1924. seria m. 740,407.

To all whom it may contain:

Be t known that I, PnnoY-VV. VAL NTIN a citizen of the United Statesfresiding at wax in a sufficiently heated condition be-' tween the point at which'the thread leaves the wax pot or thread-guiding extension thereof and the stitching ,point. In other words, its. purpose is to keep that party of the thread which is exposed to the airprior to the formation of the stitch hot enough to be workable even though the machine should stand idle. The invention is particularly useful and primarily intended for sewing machines designed to stitch leather-pas for instance those used in thema nu'factu'reof shoes, bags, harness, etc, but, except that the machinefis of a type which exposes a length of thread to the air, there is no limitation as to the type, character or make of sewing machine with which the invention may be used, or as to the operation 'for which it is provided and used.

Before describing the invention I will briefly mentionthediliiculties inthe operation of sewing machines using hot waxed thread andin stitching upon shoes and other leather articles; and in so doing I will refer for illustration to the shoe making art particularly, but without implying thereby any limitation of my claimed invention;

ter, and sets much more quickly, than cold wax, and is ofa character to make a -1nuch firmer union between the thread and the leather through which the thread 'passes' The material known by termhot wax s a wax which is hard and firm at ordinary temperaturesbut isliquefiable byfheat at a ternl' 'iwerthanenoughto 5 ""six er iii-gum the thread The sewing ee In the first place the use of a thread impregnatedwith hichthis wax is used are provided with a wax pot through whichthe thread passes and in which the wax is kept liquid by suitable heating means, usually and prefer-.

ably, an electric heating unit. The thread passes from an outlet in the bottom of the wax pot,the orifice of which is small enough to preventleakage of the viscous liquid wax, and passes to the needle and other stitch 'for-ming instruments of the sewing machine.

WVith the machine with which this invention s concerned a considerable length of the thread extends between the wax; pot outlet and the needle in order to give free scope v for the action of the stitch forming instruments, and this part of the thread is exposed to rapid coolingv by radiation and the conductlng effect of air currents. VV'hile the stitches are formed andflset in. the work so rapldly that the thread is not exposed to the cool air iong enough to permit the wax for the exposed waxed thread to, cool "and harden. Such cooling occurs in the case of machines used in shoe'making, for in} sta -nce, in even the' short interval of timelre- "the stitching machine continues in action,

qnir'ed to lay down afinished piece of work andpick up and place in position for stitching a new piece work, I Itfresults then that after each stoppage o'f'themachine the operator, just before commencing on" the next {piece ofwork, must seize the end of "the thread andpul'l it out far enough to bring a heated length to the needle. This results in wasting all the thread between the needle andthe wax pot every time the thread is thus pulled out; and the amount so wasted I.

each time isfrom afoot to a foot and ahalf. If the operator forgets to pull away the hardened. threadfthe result is difiiculty in passing the stitches through the 'wo' k and i an inferioror spoiled piece of work. Thus in order to produce satisfactory work, a 'f thread is necessary which' n the year amounts to a very substanjtial item or'each mac'hlne in use. There 1s,

also, anuappreciablereduction in the output of 'the'o'perator due to the time required for drflicultiesand objections above, re

Tli'e was to in; senate with "as off the ichilledpparts' of the ing hot waxed thread have been avoided through my invention by the application to the machine of a device which throws a concentrated beam of radiant heat upon the length of thread intervening between the needle and the wax pot, and preferably also on a part of the wax pot itself, or of an extension of the wax pot through which the thread passes before emerging into the open air. The source of heat is of a character and placed in such a location that 1t is not .a menace to theoperators safety and comgeneral character above indicated, but of any desired specific type, arranged and cooperating to the effect above indicated.

In the drawings:

I Figure 1 is a side view of a sewing machine with my heating attachment'applied thereto; I

'Fig. 2'is a front elevation of the sewing machine and associated heating attachment;

Fig.3 is a View similar to Fig. 2yand on a larger scale, but omitting the frame of the sewing machine;

Fig. 4 is a sectional view of a suitable form of heater adapted to project a beam of radiant heat; s

Fig. 5 is a perspective view of an alternatlVB form of-heating element adapted to be used as a part of the heat projector shown in Fig. 4 and in substitution for the heating element there shown.

1 Like reference. characters designate the same parts wherever they occur in all the figures.

The machine and the stitch forming instrumentalities shown in Figs. 1, 2 and 3 are those of acommercial machine put out for stitching leather bags. The numeral 11 represents the frame of the machine, 12 the table or work rest, 13 the Dresser-foot, 14 the needle, and 15 and 16 other instruments cooperating with the needle ina well-known way to form stitches. '17 represents the wax pot which issecured to the upper part of the frame of the'machine, as herefsho'wn'by bracket 18. The thread 19 passesint o the top of the wax pot around a tension guide 20 andextends throngh a tube 21, which forms an extension of the bottom of the wax pot, and emerges through a guide 22 having an orifice of a proper size to permitpassage of the thread andexclude passage of the hot Wax. The wax pot may be heated by any suitable means, such as a gas flame but preferably by an electrical heating unit which may be of any sort now used or suitable for the purpose. The outer end of such a unit is shown in Fig. 2 and a switch 23 is there shown as applied to the unit. A cable 24 contains the wire circuit for the heating unit and leads from any suitable source of electrical energy, for instance a socket inan electric lighting system.

As thus far described the machine is not essentially different from hot waxed thread sewing machines now on the market and contains nothing new except the tube 21 which extends from'the pot and forms, in effect, a part thereof, cooperating with the wax pot proper and the heating attachment in a manner presently described. For the purpose of this description the specific sewing machine herein shown and described may be considered as typical of any and all machines equipped for stitching with a hot waxed thread, and in which the thread is exposed to the surrounding air in its course to the stitch forming means.

The section of the thread lying between the outer guide 22 and the needle is exposed to the air and is subject to a rapid cooling effect. It is designated by the reference character 19*. With the machines heretofore used, this length of thread becomes cool and stiff when the machine is allowed to stand idle for any except the briefest length of time. This is the part of the thread which must be drawn off, as previously mentioned, far enough to substitute a hot length of thread from the wax pot just before starting the machine again after an idle period. My invention comprises a. means for keeping the exposed thread 19 hot and in permanent condition for sewing during any idle period heating attachment which consists of a heating unit and a projecting reflector. Said unit and reflector combination are shown in detail in Figure 4. The unit is a coil of high resistance wire 25 wound around a core 26 and connected to lead wires 27 and 28. The reflector is designated 29. It'is of generally parabolic form; in. other. words is a projecting reflector of a type having a focus and so formed that it willreflect, in a concentrated beam, rays emitted from a source of heat placed at or near the focus. It is preferably formed with a sleeve portion 30 at its apex in which the heating unit isfitted and secured. The heating unit is thereby mounted at the focal point of the reflector and in the region adjacent thereto. This combined heating unit and reflector embodies principles well-known and already used to project light or heat rays in a beam, in other environments. Itmay be embodied in other forms than that shown; for instance with the substitution of the heating unit 31 shown in Fig. 5 in place of the heating unit 25., or with reflectors adapted .to cause greater or less concentration of reflected heat rays in the space occupied by the ex posed thread. The alternative heating unit shown in Fig. 5 is one of a we-li-cknown :commercial character in which ahigh resistance conducton is ineased in-a shell, whereby it gives off heat merely and does not glow. Either unit maybe .used inplace of the other according asithelight and the intense heat of the exposed wire in the heater '25 isan advantage or a disadvantage.

The heat projector, as I may now call'the combined heating unit and reflector, is mounted on or beside the seving machine in any convenient way, for example by means of a bracket 32 attached to the side of the machine frame and having a sleeve portion to contain the sleeve of the reflector, and in a position where it is out of the way of the operator but directs its beam of heat over the space which is crossed by the exposed length 19 of the thread. The terminals of the heating unit are connected to the wires in a cable 33 and these wires turn are adapted to be connected by means of a switch 34: with the main wires in the cable 24. r

This mode of mounting the projector and connecting its heating unit in the electric circuit, illustrates one of many possible ways in which the projector may be mounted and connected, within the skill of persons skilled in the art, and Within the protection which I claim. If desired the mount which holds the projector may be equipped with provisions for adjustment, but I have not thought it necessary to illustrate such provisions as they are not an essential feature of the invention. 1 c v v.

By means of the projector I am able to direct a heat beam high enough in temperature and throwing enough heat upon the exposed thread, to maintain the thread always at the temperature where its content and coating of wax is soft and fluid enough for the proper stitching. This result may be achieved even though the temperature of the source of heat itself is not great enough to emit light, by properly designing the reliector so that enough of the heat rays will impinge on the thread. I have found that with the use of a parabolic reflector and either type of heating unit shown in these drawings, I can keep the thread warm enough for the purpose but without injuring it or the wax upon it, and without causing discomfort to the operators hands when exposed to the beam.

A further feature of the invention to which I direct'attention is the coaction of the extension tube 21 with the'wax pot proper and the heat projector. This tube and its. connection with the wax pot are large enough hitern-al-ly to contain a body of wax which flows freely from the pot.-. Itsend nearer the needle extends into the heat beam from the heat projector. Thus itis heated at both ends; one end being heated by the radiant heat from the projector and the other end byconduction from the walls the waxpot proper and the contained body of wax. The heat thus deliveredto the extension tube from both of its ends is enough to keep the wax in this tube hot enough. for thespurposes f of satisfactory stitching. The protection whichI claim is not altogether limited to such .an extension tube however, forsatisfactory results may also be obtained even with the omission of this tube and althougl'i the projected heat beam may not be as wide as the entire space between needle and the thread outlet from the wax pot.

It will be apparent that, as the exposed thread is thus kept with its content and coating of wax in a suitable'pla-stic condi tion, no matter how long the machine may stand idle, it is always in condition to re .sume stitching. at once after an idle period, and the operator does not need to draw off the exposed length of thread before commencing to stitch. .In this way the thread formerly wasted is used and the operators secureby ranged to direct a beam of radiant heat upon the thread between said wax pot and stitching instruments.

2. A sewing machine using a hot waxed thread combined with a heat projector arranged to direct a beam of radiant heat on the exposed thread'adjacent to the stitch forming instruments of the machine.

3.7In asewing machine, a wax pot arranged to receive thesewing thread in its passage to'the stitch forming instruments of said machine, means for heating said wax pot and the contained wax, and means for.

throwing a beam of radiant heat upon the region, between said wax pot and the stitching point, in which the needle and other stitch forming instruments of the machine operate on the thread to form stitches.

.4. In a sewing 'machine, a wax pot arranged to receive the sewing thread in its r passage to f the I stitch forming instruments of said machme, means for heating sald wax 'pot and the containedwax, and means for throwing a beam of radiant-heat upon the region, between said wax pot and the stitchingpoi-nt, whichthe needle" and other stitch forming lnStIuHilliZS of the machine operate on the thread to form stitches, said wax pot having a. tubular extension through which the thread passes and the outer end of which extends into said beam.

r 5. A. sewing machine adapted to stitch with a hot waxed thread, a wax pot associated with said machine through which the thread is adapted to pass on its way to the stitching point, means for heating said wax pot and the contained wax, the wax pot having an extension through which the thread passes and in which wax is contained in communication with the main body of wax in'the pot, and a heat projector comprising a source of heat, and a projecting reflector surrounding said source, arranged to direct a concentrated heat beam upon the end of said extension tube and the space through which the thread passes between said extension tube and the stitching point.

6. In a sewing machine, stitch forming means, a heated wax pot, through which the thread for stitching is caused to pass on its way to said means, there being between the outlet from the wax pot and said means an open space which the thread crosses and in which the thread'is exposed to the cooling effect of the surrounding air, and means for heating thevthread in said open space.

7. In a sewing machine, stitch forming means, a heated wax pot, through which the thread for stitching is caused to pass on its way to said means, there being between the outlet from the wax pot and said means an open space which the thread crosses and in which the thread is exposed to the cooling effect of the surrounding air, and a'heat projector arranged at one side of the course of the thread and constructed to project a being between the outlet from the wax pot' andsaid instruments an open space which the thread crosses and in which the thread is'expesed to the cooling eflect of the surrounding air, an electrical heating unit at one side of the course of the thread, and a projecting reflector constructed and arranged in association with said unit to project a concentrated beam of radiant-heat from said heating unit upon thethread in said open space.

9. The combination with a sewing machine and a heated. pot of wax through which the thread passes in its course tothe stitching instruments, or" a heat projector comprising a projecting reflector and a source of heat substantially at the focal point of said reflector, arranged to direct a beam of radiant heat upon the thread be tween said wax pot and stitching instruments. 7

10. In combination with a sewing machine having a heated wax pot, means for heating the thread used by said machine where such thread is exposed to the cooling effect of the outer air; said means consisting of a heating unit and a reflector arranged to reflect heat rays from said unit in a concentrated beam upon the thread so exposed.

In testimony whereof I have affixed my signature.

PERCY W. VALENTINE.- 

